/*
 * Copyright (c) 2007, 2015, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 2001-2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: ProcessingInstructionPattern.java,v 1.2.4.1 2005/09/12 11:04:08 pvedula Exp $
 */

package com.sun.org.apache.xalan.internal.xsltc.compiler;

import com.sun.org.apache.bcel.internal.generic.BranchHandle;
import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen;
import com.sun.org.apache.bcel.internal.generic.GOTO;
import com.sun.org.apache.bcel.internal.generic.IFEQ;
import com.sun.org.apache.bcel.internal.generic.IF_ICMPEQ;
import com.sun.org.apache.bcel.internal.generic.INVOKEINTERFACE;
import com.sun.org.apache.bcel.internal.generic.INVOKEVIRTUAL;
import com.sun.org.apache.bcel.internal.generic.InstructionHandle;
import com.sun.org.apache.bcel.internal.generic.InstructionList;
import com.sun.org.apache.bcel.internal.generic.PUSH;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError;
import com.sun.org.apache.xml.internal.dtm.Axis;
import com.sun.org.apache.xml.internal.dtm.DTM;

/**
 * @author Morten Jorgensen
 */
final class ProcessingInstructionPattern extends StepPattern {

  private String _name = null;
  private boolean _typeChecked = false;

  /**
   * Handles calls with no parameter (current node is implicit parameter).
   */
  public ProcessingInstructionPattern(String name) {
    super(Axis.CHILD, DTM.PROCESSING_INSTRUCTION_NODE, null);
    _name = name;
    //if (_name.equals("*")) _typeChecked = true; no wildcard allowed!
  }

  /**
   *
   */
  public double getDefaultPriority() {
    return (_name != null) ? 0.0 : -0.5;
  }

  public String toString() {
    if (_predicates == null) {
      return "processing-instruction(" + _name + ")";
    } else {
      return "processing-instruction(" + _name + ")" + _predicates;
    }
  }

  public void reduceKernelPattern() {
    _typeChecked = true;
  }

  public boolean isWildcard() {
    return false;
  }

  public Type typeCheck(SymbolTable stable) throws TypeCheckError {
    if (hasPredicates()) {
      // Type check all the predicates (e -> position() = e)
      final int n = _predicates.size();
      for (int i = 0; i < n; i++) {
        final Predicate pred = (Predicate) _predicates.elementAt(i);
        pred.typeCheck(stable);
      }
    }
    return Type.NodeSet;
  }

  public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
    final ConstantPoolGen cpg = classGen.getConstantPool();
    final InstructionList il = methodGen.getInstructionList();

    // context node is on the stack
    int gname = cpg.addInterfaceMethodref(DOM_INTF,
        "getNodeName",
        "(I)Ljava/lang/String;");
    int cmp = cpg.addMethodref(STRING_CLASS,
        "equals", "(Ljava/lang/Object;)Z");

    // Push current node on the stack
    il.append(methodGen.loadCurrentNode());
    il.append(SWAP);

    // Overwrite current node with matching node
    il.append(methodGen.storeCurrentNode());

    // If pattern not reduced then check kernel
    if (!_typeChecked) {
      il.append(methodGen.loadCurrentNode());
      final int getType = cpg.addInterfaceMethodref(DOM_INTF,
          "getExpandedTypeID",
          "(I)I");
      il.append(methodGen.loadDOM());
      il.append(methodGen.loadCurrentNode());
      il.append(new INVOKEINTERFACE(getType, 2));
      il.append(new PUSH(cpg, DTM.PROCESSING_INSTRUCTION_NODE));
      _falseList.add(il.append(new IF_ICMPEQ(null)));
    }

    // Load the requested processing instruction name
    il.append(new PUSH(cpg, _name));
    // Load the current processing instruction's name
    il.append(methodGen.loadDOM());
    il.append(methodGen.loadCurrentNode());
    il.append(new INVOKEINTERFACE(gname, 2));
    // Compare the two strings
    il.append(new INVOKEVIRTUAL(cmp));
    _falseList.add(il.append(new IFEQ(null)));

    // Compile the expressions within the predicates
    if (hasPredicates()) {
      final int n = _predicates.size();
      for (int i = 0; i < n; i++) {
        Predicate pred = (Predicate) _predicates.elementAt(i);
        Expression exp = pred.getExpr();
        exp.translateDesynthesized(classGen, methodGen);
        _trueList.append(exp._trueList);
        _falseList.append(exp._falseList);
      }
    }

    // Backpatch true list and restore current iterator/node
    InstructionHandle restore;
    restore = il.append(methodGen.storeCurrentNode());
    backPatchTrueList(restore);
    BranchHandle skipFalse = il.append(new GOTO(null));

    // Backpatch false list and restore current iterator/node
    restore = il.append(methodGen.storeCurrentNode());
    backPatchFalseList(restore);
    _falseList.add(il.append(new GOTO(null)));

    // True list falls through
    skipFalse.setTarget(il.append(NOP));
  }
}
